Elevator hoistway door interlock



Aug. 23, 1966 B. w. TUCKER, JR 3,268,679

ELEVATOR HOISTWAY DOOR INTERLOCK Filed Nov. 1.7, 1964 3 Sheets-Sheet l NITROGEN FIG. I

BENJAMIN WHITEHEAD TUCKER JR.

INVENTOR BY WOZWTTQRNEY 3, 1966 B. w. TUCKER, JR 3,263,679

ELEVATOR HOISTWAY DOOR INTERLOCK Filed NOV- 17, 1964 5 Sheets-Sheet 2 FIG. 2

BENJAMIN WHITEHEAD TUCKER JR.

FIG. 3 INVENTOR BY W W ATTORNEY Aug. 23, 1966 3 w TUCKERY'JR 3,268,679

ELEVATOR HOISTWAY DOOR INTERLOCK Filed Nov. 17, 1964 5 Sheets-Sheet 5 BENJAMIN WHITEHEAD TUCKER JR.

INVENTOR BY ATTORNEY United States Patent 3,268,679 ELEVATOR HOISTWAY DOOR INTERLOCK Benjamin Whitehead Tucker, Jr., South Orange, N.J., assignor to Otis Elevator Company, New York, N.Y., a corporation of New Jersey Filed Nov. 17, 1964, Ser. No. 411,833 3 Claims. '(Cl. 200-6164) This invention relates generally to elevator hoistway door interlocks and particularly to interlocks in which the electric contacts are totally enclosed.

Elevator hoistway door interlocks usually comprise a mechanical lock and an electric switch in which the circuit through the switch can be completed only after the door has been locked closed and in which the door can be unlocked only after the circuit has been interrupted. Elevators are sometimes required to operate in hostile environments such as those in which the atmosphere includes explosive or corrosive gases. Such environments present problems of explosion hazards due to sparking at the contacts and/or deterioration of the contacts due to corrosion. One partial solution to the problem utilizes a so-called explosion proof switch which operates on the principle of confining any possible explosion to the vicinity of the switch. The contacts are enclosed in a strong case and are actuated by a plunger extending through a long bushing so that a flame occurring within the case cannot be propagated to the exterior of the case. Another partial solution operates on the principle of keeping the hostile environment away from the contacts and utilizes a commercially available moisture resistant switch. Such a switch typically comprises a plunger operated spring return switch enclosed in a gas tight case in which the protruding plunger is surrounded by a cup shaped flexible sheath sealed to the body of the case. The switch is operated by an actuator bearing against the sheath and depressing the plunger. Withdrawal of the actuator allows the internal spring to re-extend the plung er and open the contacts. Neither of the above solutions is entirely satisfactory for use with hoistway door interlocks. For example, in the former case, there is always a chance that an interior flame will leak outside the case either through the space between the bushing and plunger or by rupture of the case. Additionally, the absence of a complete seal allows corrosive gases to enter the case and cause deterioration of the contacts. In the latter case, the switch is positively actuated in one direction only, the internal spring being relied upon to open the circuit. Accordingly, there is a possibility of the contacts remaining closed when the actuator is withdrawn due to sticking of the contacts themselves or of other parts. Additionally, repeated operation causes abrasion of the sheath by the actuator, leading to the likelihood of early failure.

It is a general object of the present invention to provide an improved hoistway door interlock.

Another object is to provide a hoistway door interlock suitable for use in hostile environments such as one in which the atmosphere contains explosive or corrosive ases. g Another object is to provide a hoistway door interlock suitable for use in hostile environments in which the electric circuit can be and is completed only after the door is mechanically locked and in which the door cannot be unlocked until the electric circuit is interrupted.

Briefly stated, the invention comprises a switch enclosed in a stationarily mounted airtight case. The switch includes two stationary contacts, the circuit between which is completed when they are engaged by a movable bridging contact member. The latter is actuated by a rod fastened thereto one end of which projects through an ice aperture in the case. The airtight seal is maintained by a resilient extensible sleeve within the case surrounding the rod, one end of which is sealed to the rod while the other end is sealed to the case in the region surrounding the aperture.

A latch is fastened to the hoistway door for movement therewith and is formed with a flat surface which cooperates with a similar flat surface fastened to the case and constituting a catch. The latch is pivotally mounted and is spring biased for rotation in a direction to bring its flat surface in juxtaposition to the corresponding surface of the catch when the door is closed, therebylocking the door.

A rigid U shaped member has one leg fastened to the projecting end of the rod substantially perpendicular thereto. The U shaped member, the rod and the catch are so positioned that as the door closes, the end of the latch enters the open end of the U and engages that leg fastened to the rod as the latch is rotated into locking position by the spring. Thus, as the door is locked, the rod pushes the bridging member into engagement with the contacts, completing the circuit. Before the door can be opened, the latch must be rotated out of engagement with the catch, and when so rotated, the end of the latch engages the other leg of the U, thereby withdrawing the bridging member from the contacts.

For a clearer understanding of the invention reference may be made to the following detailed description and the accompanying drawing, in which:

FIGURE 1 is an elevation view of an interlock according to the invention taken from within the hoistway between the car and hoistway doors looking toward the hoistway door, with certain parts broken away;

FIGURE 2 is a fragmentary cross section view, taken on the line 2-2 of FIGURE 1; and

FIGURES 3, 4 and 5 are views similar to FIGURE 1 showing the parts in various positions during operation of the invention.

Referring first to FIGURE 1 there is shown a case 11 bolted to the stationary door jamb or the building structure 12. Within the case is mounted a switch 13 which includes an insulating frame 14, and a pair of contacts 15, supported on spring arms 16. The contacts 15 are electrically connected to terminals 17 which, in turn, are connected to a pair of conductors 18. These conductors pass through an aperture in the case 11 which is sealed with a rubber bushing 19 or other suitable material.

A contact base 21 has a conductive metal bar 22 fastened to the top thereof which cooperates with the contacts..15 to complete an electrical circuit. The base 21 is fastened to a rod 23 which passes through an aperture in a bushing 24 with a freely slidable fit. The outside of the bushing 24 makes a very tight fit in an aperture in the case Hand is effectively a part thereof. A flexible bellows 25 made, for example, of silicone rubber, embraces the rod 23 and has its upper end fastened thereto by means of a clamp 26. The lower end of the bellows embraces a reduced diameter portion of the bushing 24 and is fastened thereto by means of a clamp 27. It is apparent that as ..the rod 23 is moved upward to the position shown in FIGURE 1 a circuit is completed between the terminals 17 while when the rod is moved downward the circuit is opened. The portion of the apparatus so far described is tightly sealed by means of a cover 28 and a gasket 29. Thus, it is apparent that the interior of the case 11 is isolated from the exterior and that ambient gases, corrosive, explosive or otherwise cannot enter the case. In some cases, even further precautions against explosions may be necessary and in such circumstances the interior of the case may be filled with a gas such as nitrogen which will not support combustion. Shown schematically in FIGURE 1 is a source 31 of nitrogen connected by suitable piping 32 to the interior of the case 11. A valve 33 mounted in the wall of the case 11 may be opened when it is desired to flood the case with nitrogen so that the entrapped air may be bled off and replaced with nitrogen.

A U-shaped bracket 35 has one leg thereof fastened to that portion of the rod 23 which extends outside the case 11. The rod may be fastened, for example, by means of pin 36 and may protrude slightly through the leg of the U but this is not essential. The opposite leg of the U shaped bracket is formed with an aperture aligned with the rod 23 which aperture makes a sliding fit with a pin 37 which is rigidly fastened to a stationary member 38. It is apparent that the U bracket 35 may slide up and down on the pin 37 and in so doing will complete or interrupt the circuit between the contacts 15.

A hoistway door 41 is mounted for horizontal movement by any suitable hanger arrangement (not shown). The door 41 is urged to its closed position which is to the left as viewed in FIGURE 1, by a spring 42 having one end fastened to the door and the other end fastened to the building structure 43. In its fully closed position, as illustrated in FIGURE 1, the door 41 rests against a stop member 44 which also is fastened to the building structure 43. A bracket is bolted to the door 41 and carries a lower horizontal portion 45 and an upper vertically extending portion 46. A lock mechanism 47 is fixedly mounted to the bracket 46 about a stub shaft 48. The lock mechanism includes an upwardly extending arm 51 against which bears a compression spring 52 which is held in place by means of bolt 53 fastened to the bracket 46. The spring 52 urges the lock mechanism clockwise as viewed in FIGURE 1. The lock mechanism 47 includes a latch portion 54 which is formed with a surface 55 extending in an approximately vertical plane. This surface cooperates with a similar surface 56 formed on a catch 57 which, in turn, is fastened to the case 11. With the parts in the positions shown in FIG- URE 1, the door is locked and the surfaces 55 and 56 are in juxtaposition.

The latch 54 includes a tripper portion 58 which extends into the open end of the U bracket 35. The upper portion of the tripper 58 is formed with a slightly concave surface so that in spite of manufacturing tolerances and various positions of the tripper 58, this surface remains approximately horizontal as it engages the upper leg of the U bracket 35 (or the lower end of the rod 23 if this rod projects through as shown in FIGURE 1). The lock assembly includes a downwardly extending arm portion 61 which cooperates with a stop member 62 fastened to the bracket 46 so as to limit counterclockwise rotation of the lock assembly. The lower end of the arm 61 also carries a roller 63 which, as will be fully explained, cooperates with a vane on the car door.

The lower portion 45 of the hoistway door bracket also carries a bell crank lever 65 which is pivoted thereto by means of a shaft 66. Two rollers 67 and 68 are mounted at opposite ends of the lever 65 as shown. A torsion spring 69 about the shaft 66 urges the lever 65 to rotate in a counter clockwise direction as viewed in FIGURE 1. When the door is closed, as shown in FIGURE 1, the roller 67 bears against a stop member 71 fastened to a stationary frame member 72.

As best shown in FIGURE 2 a car door 75 has fastened thereto a bracket 76 to which, in turn, is fastened a vane 77 which cooperates with the rollers 63 and 68. These rollers are mounted so as to project from the hoistway door 41 toward the car door 75 and are positioned approximately within the space between the edge 78 of the hoistway sill and the edge 79 of the car sill. When the car and hoistway doors are fully closed as shown in FIG- URES 1 and 2, the vane 77 does not engage either the roller 63 or the roller 78 but is spaced from each so that as a car passes a hoistway door at which no stop is to be made there will be no engagement between the moving vane and the stationary rollers.

FIGURE 1 shows the parts with the door 41 fully closed and engaging the stop member 44. The door is mechanically locked by the juxtaposition of the surfaces and 56. A circuit is completed between the contacts 15.

The door is opened by a movement of the car door to the right which moves the vane 77 into contact with the roller 63. At first, the door 41 does not move but the lock mechanism is rotated counterclockwise thereby drawing the tripper 58 into contact with the lower leg portion of the U bracket 35 thus positively withdrawing the contact base 21 away from the contacts 15. FIGURE 3 shows the position of the parts before the counterclockwise rotation of the lock 47 has been completed. The contact base has been drawn downwardly sufficient to allow the spring arms 15 to extend fully but contact has not yet been broken. The surface 55 has not yet been drawn below the level of the surface 56.

Further rotation of the lockmechanism 47 brings the parts to the positions shown in FIGURE 4. The contact base 211 has been fully withdrawn and the surface 55 is now below the level of the surface 56 so that the door can be opened. The arm portion 61 of the lock mechanism now engages the stop member 62 so that further movement of the vane 77 causes the hoistway door 41 to be moved to the right as shown in FIGURE 5. During this movement the spring 69 rotates the bell crank lever '65 counterclockwise until the roller 67 engages an abutment 81 on the bracket 45. At the same time the roller 68 engages the vane 77 so that the latter is clamped between this roller and the roller 63. The parts illustrated maintain this position as the door is fully opened.

When the door is closed the vane 77 moves to the left and bears against the roller 68. The axis of the roller 68 is aligned with the pivot axis 66 so that there is no tendency at this time to rotate. the bell crank lever 65. As the door approaches the closed position, as illustrated in FIGURE 5, the door operator mounted on the car door (not shown) holds back the vane 77 which, in turn, bears against the roller 63 to decelerate the door 41 against the urging of [the spring 42. As the door approaches the position shown in FIGURE 4 the roller 6-7 engages the stop '71 thereby rotating the lever clockwise to the position shown in FIGURE 4. At the same time the tripper '58 enters the open end of the U bracket 35. The door \51 is now fully closed and engages the stop member 44. However, the car door and the vane 77 continue to move to the t-left allowing the spring 52 to rotate the lock mechanism 47 clockwise as shown in FIGURE -3. The door is now locked because the surface 55 has been moved upward and is partially opposite the surface 56. Further motion of the vane 77 to the left allows the lock mechanism 47 to rotate further counterclockwise thus raising the contact member 21 into engagement with the contacts 15.

It is apparent that the present invention provides an improved hoistway door interlock. The contacts are completely enclosed 'and isolated from the ambient atmosphere even without the introduction of the nitrogen. The nitrogen atmosphere is not necessary in all cases and may sometimes be omitted. The contacts are positively made by rotation of the member 47 but they cannot be made until the door is mechanically locked. Similarly the circuit is positively broken before the door is mechanically unlocked. There is no reliance on an internal spring to break the contacts. There is no direct abrasion of a flexible sealing element by an operating member, the only wear being that due to flexure.

Although a specific embodiment of the invention has been described in considerable detail for illustrative purposes many modifications will occur to those skilled in the art. It is therefore desired that the protection afforded by Letters Patent be limited only by the true scope of the appended claims.

What is claimed is:

1. A hoistway door interlock, comprising,

a pair or stationary contacts,

a bridging contact member,

a rod tastened to said member for moving said member into and out of engagement with said stationary con tacts,

an airtight case surrounding said contacts and said bridging member and stormed with an aperture through which said rod projects with a sliding fit,

a flexible bellows within said case surrounding said rod 'having one end sealed to said rod and the other end sealed to said case in the region of said aperture, whereby the interior of said case is isolated from the surrounding atmosphere,

a generally U shaped bracket including first and second leg portions and a base portion,

the pnojectign end of said rod being fastened to said first leg portion substantially perpendicular thereto leaving a space between said leg portions,

said second leg portion being tormed with an aperture in alignment with said rod,

a pin stationarily mounted in alignment with and projecting into said aperture in said second leg portion with a sliding fit,

whereby said bridging member, said rod and said bracket are moveable as a unit longitudinally of said rod,

a hoistway door,

a latch mounted on said door and projecting into the space between said leg portions when said door is closed,

whereby movement of said latch in a direction substantially parallel to the axis of said rod alternatively either completes or interrupts the circuit between said contacts, and

a stationarily mounted catch cooperating with said latch to lock said door when said latch is moved in a direotion to complete said circuit.

2. A hoistway door interlock, comprising,

a pair of stationary contacts,

a bridging contact member,

a rod fastened to said member for moving said member into and out of engagement with said stationary contacts,

an airtight case surrounding said contacts and said bridging member and formed with an aperture through which said rod projects with a sliding fit,

a flexible bellows within said case surrounding said rod having one end sealed to said rod and the other end sealed to said case in the region of said aperture,

whereby the interior of said case is isolated trom the surrounding atmosphere,

a generally U shaped bracket including lfirst and second leg portions and a base portion,

the protecting end of said rod being fiastened to said first leg portion substantially perpendicular thereto leaving a space between said leg portions,

said second leg portion being formed with an aperture in alignment with said rod,

a pin stationarily mounted in alignment with and projecting into said aperture in said second leg portion with a sliding fit,

whereby said bridging member, said rod and said bracket are movable as a unit in a direction parallel to the axis of said rod,

a catch stationarily mounted on said case,

a hoistway door mounted to be slidable between an open and -a closed position,

an elongated latch having one end pivotally mounted on said door with the other end having limited movement in a direction substantially perpendicular to the direction of door movement,

said latch and said catch each being formed with a projecting planar surtace which surfiaces cooperate to lock said door in its closed position,

said latch and said catch being relatively positioned so that pivotal movement of said latch while said door is closed brings said surf-aces into and out of juxtaposition thereby locking and unlocking said door,

said bracket being positioned relative to the path of movement of said latch so that said other end of said latch enters the space between and is embraced by said leg portions when said door closes,

whereby, while said door is closed, pivotal movement of said latch in one direction locks said door and completes a circuit between said contacts and pivotal movement in the other direction interrupts said circuit and unlocks said door.

3. Apparatus according to claim 2 further comprising means for filling the interior of said case with nitrogen.

References Cited by the Examiner UNITED STATES PATENTS 1,525,215 2/ 1925 Wolff 200-6165 2,854,566 9/ 1958 Beer v200-16 8 X 2,981,813 4/1961 Jennings ZOO-144- B'ERNARD A. GILHEANY, Primary Examiner.

J. J. BAKER, Assistant Examiner. 

1. A HOISTWAY DOOR INTERLOCK, COMPRISING A PAIR OF STATIONARY CONTACTS, A BRIDGING CONTACT MEMBER, A ROD FASTENED TO SAID MEMBER FOR MOVING SAID MEMBER INTO AND OUT OF ENGAGEMENT WITH SAID STATIONARY CONTACTS, AN AIRTIGHT CASE SURROUNDING SAID CONTACTS AND SAID BRIDGING MEMBER AND FORMED WITH AN APERTURE THROUGH WHICH SAID ROD PROJECTS WITH A SLIDING FIT, A FLEXIBLE BELLOWS WITHIN SAID CASE SURROUNDING SAID ROD HAVING ONE END SEALED TO SAID ROD AND THE OTHER END SEALED TO SAID CASE IN THE REGION OF SAID APERTURE, WHEREBY THE INTERIOR OF SAID CASE IS ISOLATED FROM THE SURROUNDING ATMOSPHERE, A GENERALLY U SHAPED BRACKET INCLUDING FIRST AND SECOND LEG PORTIONS AND A BASE PORTION, THE PROJECTING END OF SAID ROD BEING FASTENED TO SAID FIRST LEG PORTION SUBSTANTIALLY PERPENDICULAR THERETO LEAVING A SPACE BETWEEN SAID LEG PORTIONS, SAID SECOND LEG PORTION BEING FORMED WITH AN APERTURE IN ALIGNMENT WITH SAID ROD, A PIN STATIONARILY MOUNTED IN ALIGNMENT WITH AND PROJECTING INTO SAID APERTURE IN SAID SECOND LEG PORTION WITH A SLIDING FIT, WHEREBY SAID BRIDGING MEMBER, SAID ROD AND SAID BRACKET ARE MOVEABLE AS A UNIT LONGITUDINALLY OF SAID ROD, A HOISTWAY DOOR, A LATCH MOUNTED ON SAID DOOR AND PROJECTING INTO THE SPACE BETWEEN SAID LEG PORTIONS WHEN SAID DOOR IS CLOSED, WHEREBY MOVEMENT OF SAID LATCH IN A DIRECTIION SUBSTANTIALLY PARALLEL TO THE AXIS OF SAID ROD ALTERNATIVELY EITHER COMPLETES OR INTERRUPTS THE CIRCUIT BETWEEN SAID CONTACTS, AND A STATIONARY MOUNTED CATCH COOPERATING WITH SAID LATCH TO LOCK SAID DOOR WHEN SAID LATCH IS MOVED IN A DIRECTION TO COMPLETE SAID CIRCUIT. 